1. Field of the Invention
This invention relates to the use of the magnetic flux exclusion in certain superconducting compositions for the operation of cryotrons and magnetic storage devices.
2. Background
Magnetic storage devices rely on large numbers of bistable elements to store information. The two stable states of each element correspond to the two logical states of the binary memory storage device, e.g., "zero" and "one". Heretofore, magnetic storage devices have utilized various semiconductor devices involving integrated circuit elements or various magnetic devices involving materials such as magnetic cores and/or magnetic thin films.
The cryotron is a device that performs some of the functions of an electron tube and utilizes the fact that a changing magnetic field can cause a superconductive element to oscillate between a state of low and high resistance. By imposing the magnetic field resulting from a current passing through a control element on the superconductive element, the latter can be switched from its superconducting state to its normal state. As a result, the current in the superconductor can be periodically eliminated or restored and the absence or presence of the current can correspond to the two logical states of the binary memory cell.
However, it should be noted that none of these devices of the prior art utilizes the magnitude of the magnetic flux exclusion of a superconducting composition as a measure of the logical state of the element. Furthermore, none of the superconducting compositions of the prior art could be employed in such devices at temperatures above 77K (liquid nitrogen).